Temperature and shape control system for rolling mill rolls

ABSTRACT

A temperature and shape control system for rolling mill rolls operable to extract heat or add heat to the roll ends of the back-up rolls to produce and maintain a heat balance and temperature gradient across the width of the roll bodies to maintain the desired roll shape for determining and improving the flatness of the product being produced in the rolling mill.

United States Patent Hacker et al.

TEMPERATURE AND SHAPE CONTROL SYSTEM FOR ROLLING MILL ROLLS Robert W.Hacker, Massillon; Wyn E. McCoy, Canton, both of Ohio The TimkenCompany, Canton, Ohio Nov. 4, 1971 Inventors:

Assignee:

F iled:

Appl. No.:

US. Cl. 72/13, 72/201 Int. Cl B2lb 37/10, B21b 27/06 Field of Search72/13, 200, 237,

References Cited UNITED STATES PATENTS 8/1903 Thompson 72/200 4/1960 VonDer l-leide 72/200 10/1934 Clark 72/200 1451 June 26,1973

1,982,571 11/1934 Clark 72/201 1,936,582 11/1933 Clapp et a]. 72/200 42,431,473 10/1947 Flynn 257/2 1,988,679 1/1935 Badlam 72/201 2,692,11810/1954 Holloway 72/200 x 2,243,010 5/1941 lversen 72/200 3,604,2379/1971 Kawanami 72/201 Primary Examiner-Milton S. MehrAttorney-Frederick M. Woodruff et a1.

ABSTRACT A temperature and shape control system for rolling mill rollsoperable to extract heat or add heat to the roll ends of the back-uprolls to produce and maintain a heat balance and temperature gradientacross the width of the roll bodies to maintain the desired roll shapefor determining and improving the flatness of the product being producedin the rolling mill.

7 Claims, 6 Drawing Figures PATENTEUJUN 26 I973 SIEHUUC FIG 4TEMPERATURE AND SHAPE CONTROL SYSTEM FOR ROLLING MILL ROLLS BRIEFDESCRIPTION OF THE INVENTION This invention relates to improvements intemperature and shape control provisions for rolling mills and isespecially directed to improvements in maintaining and controlling theheat balance and temperature gradients across the width of the rollbodies by controlling roll neck temperatures.

In high speed strip mills a major problem is the control of the stripflatness. Flatness is effected by many variables which are continuouslychanging. For example, flatness varies with changes in the materialbeing rolled, the strip thickness and width, the amount of re duction,the temperature and hardness characetistics of the strip passing betweenthe rolls, the temperature of the rolls themselves, the degree of rollwear, and the degree of tension exerted on the strip during its passagethrough the rolling mill. It is an extremely difficult problem tocoordinate all of the variables so as to produce a substantially uniformflatness throughout the strip as it comes out of the rolling mill. Anumber of variables have been referred to above and it is known fromactual practice that some of these variables change during a daysoperation of the rolling mill. Others change gradually from one end ofthe strip coil to the other, some of the variables make abrupt changesfrom one coil to another andsome variables make abrupt changes within asingle coil.

It is presently known that methodsused to correct some of thesevariables include back-up roll and work roll bending to a predeterminedcurvature, the application of cooling sprays and work roll and/r backuproll crowns.

It is a general object of the present invention to provide a temperatureand shape control system for rolling mill rolls which may have utilityby itself, as well as in combination with other means of known characterfor controlling shape.

It is an object of the present invention to provide improved shapecontrol for rolling mill rolls through the control of the heat at thebearings which support the roll necks so that the strip flatness can bemade substantially constant across its width during strip rollingoperations.

It is a further object of the present invention to provide an improvedsystem for controlling the shape of rolling mill rolls by theutilization of a heat transfer fluid medium applied to the roll necks inthe critical areas thereof supported by the bearings.

Still another object of the present invention is to provide theimprovements heretofore stated and to combine therewith means to controlthe heat balance and temperature gradient across the rolling mill rollsby modulating the flow of the heat transfer fluid.

Other objects and advantages of the present invention will be set forthhereinafter in more detail, and it is intended to include the variouselements, parts and components which are particularly set forth anddescribed.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is best seen inconnection with the accompanying drawings which set forth presentlypreferred embodiments, and wherein:

FIG. 1 is a somewhat schematic end elevational side view of a rollingmill having work rolls and back-up rolls arranged in a generallyconventional manner and wherein portions of the presently improvedtemperature and shape control system may be seen;

FIG. 2 is a fragmentary and partial sectional elevational view of therolling mill taken at line 2-2 of FIG. I particularly showing the meansby which the temperature of the back-up roll necks may be controlled inaccordance with this invention;

FIG. 3 is a fragmentary and greatly enlarged sectional view along theline 3-3 in FIG. 1 to show details of a roll neck and bearing supporttherefor with a typical temperature and shape control system;

FIG. 4 is a fragmentary end elevational view of a back-up roll chockprovided with a modified temperature and shape control system, the viewbeing typical of both back-up rolls of the rolling mill shown in FIG.

FIG. 5 is a fragmentary sectional view taken at line 5-5 in FIG. 4', and

FIG. 6 is a fragmentary view of means to control the fluid circulatingvalves, such as the character of means shown in FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIGS. 1 and 2 ofthe drawings, there is shown a preferred rolling mill arrangement whichcomprises a typical four-high rolling mill stand having the usual pairof mill housings, one of which is seen at 10. The mill is used to rollflat strip materials S. Since there are a pair of housings for eachstand, it is understood that the description of one housing will applyequally to the other. The mill housing 10 supports the necks of a pairof work rolls 11 and 12 and a pair of back-up rolls l3 and 14. Work roll11 is backed up by roll 13 and work roll 12 is backed up by roll 14. Thework rolls l1 and 12 are suitably mounted in chocks l5 and 16respectively, and the back-up rolls are slidably mounted in chocks 17and 18 so as to be vertically adjustable for back-up roll and for workroll diameter variations. The adjustable chock 17 supports the backuproll 13 and the embodiment shown enables both the work roll 11 and itsback-up roll 13 to be moved simultaneously relative to the work roll 12and its back-up roll 14 for thickness control of the strip being rolled.The work roll 12 has its chock 16 suitably mounted in the supportingchock 18 for the back-up roll 14, and in this case the chock 18 isrested in the mill housing 10 on a suitable bearing plate 19. The meansfor adjusting the work rolls 11 and 12 is generally shown at theadjusting screw 20 operatively mounted in the upper end of the millhousing 10 and connected'in a suitable manner to the thrust bearing unit21 engaged on the upper end of the chock 17 for the upper back-up roll13 and work roll 11.

Referring now to FIGS. 2 and 3, it can be seen that the upper back-uproll 13 is typically provided with roll necks 13a, each of which isoperatively mounted in a four row tapered roller bearing 22 engagedbetween the roll neck 13a and the chock 17 in mill housings 10. Theback-up roll 14 is mounted in a similar manner at necks 14a so that theview of FIG. 3 will suffice for all of the roll neck mountings.

The initial set up for the mill is to have the work rolls 11 and 12 andthe back-up rolls l3 and 14 cylindrical or with some preconceivedspecial crown which will tend to counteract deformations imposed bynormal rolling loads and thereby produce a flat strip. The achievementsought is to maintain this initial setting by counteracting the effectsof temperature and wear or to modify the initial setting if and whenrequired to produce a flatter strip. It has been found that heatexchange fluid circulated in the back-up roll bearing areas will keepthe initial desired shape of such rolls over substantially all milloperating conditions. The heat exchange fluid is circulated in such away that a balance is obtained between the heat picked up from the workreduction and the heat picked up from the baring load reaction.

In the view of FIGS. 2 and 3 the temperature control fluid for the rollneck 13a is supplied through a swivel coupling 25 which receives thesupply of control fluid which is directed by a conduit 26 at oppositesides of the stand axially through the roll neck 13a and into the innerend portion of bore 27 (FIG. 3) in the back-up roll 13. The tube 26penetrates the axial bore 27 and is smaller in diameter so as to providean annular passage 28 for the fluid return flow outside of an enclosingsleeve 29 to isolate the return fluid in the annular passage 28 from thesupply fluid within the tube 26. The return fluid is conducted awaythrough conduit 30 which is associated with or as a part of the fitting25.

In FIG. 1 a combined complete system is disclosed, with some portionsshown in schematic outline. The showing includes a roll neckrecirculating system where the fluid is moved by a pump 31 through afilter 31A into branch conduits 32 at each side, and the fluid flows outthrough the T-fittings. One such T-fitting 33 (FIG. 1) conducts thefluid into a fitting 25 of the character shown in FIG. 3. The returnflow is conducted by lines 30 to a return conduit 34 at T-fittings 35,and from conduit 34 the fluid flows to a heat exchanger unit 37, andthence to the pump 31 for recirculation. The return fluid flow toconduit 34 from each fitting 25 is controlled by a suitable valve 38which is modulated under the control response of temperature measuringthermocouple probes 39 mounted in the chocks 17 and 18 (FIG. 2) adjacenthe roll neck bearings 22 so as to be responsive to the temperature atthese hearings.

Also, as may be seen in FIG. 1, part of the combined system includes asystem where the fluid from conduit 32 flows from T-flttings 40 toconduits 41 respectively connected to jacket spaces 42 in the chocks l7and 18. From the jacket spaces 42 the fluid is conducted by cross-overpassages 43 to jacket spaces 44 at the opposite sides of the roll neckbearings 22 where the fluid exits at conduits 45 to the return conduit34 through individual flow regulating valves 36 to T-fittings 47 inreturn line 34. The valves 36 may be manually regulated, but in the viewshown they are automatically controlled by means 48 responsive throughlead 48 to the temperature at the thermocouple probes 39 used to controlthe valves 38 in the roll neck heat control system. In the manner shown,fluid is circulated into the roll necks 13a and through the chocksaround the neck bearings 22 so that the temperature across the back-uprolls l3 and 14 is controlled to avoid roll distortion due to the heatof rolling the strip material S or heat from the hearings or seals,thereby assuring flatness and accuracy of the thickness of the stripmaterial S.

There is shown in FIGS. 4 and a modified system for temperature controlof the roll neck bearings in the chock 17 for the upper back-up roll 13.In these views a header manifold 50 receives the fluid flow at end 51.The manifold is provided with a plurality of (4 being seen) outletconduits 52 (FIG. 5) which extend axially into bores 53 in the chock 17along side the roll neck bearings. The conduits 52 are smaller than thebore so as to form an annular flow passage 54 which leads into thereturn housing 55 so that the fluid may flow out at nipple 56 and intothe return manifold 57 for exit at the manifold outlet end 58. The inletend 51 of manifold 50 is adapted to be connected at T-fitting 40 byconduit 41 (FIG. 1) and the end 58 of the manifold 57 is connected toT-fitting 47 by conduit 45 (FIG. 1).

The assembly shown in FIG. 4 also includes the provision of fluidcirculating means 60 and 61 adjacent the roll neck bearing but below andat each side of the axis of the roll neck at approximately 45 from eachside of the vertical. The devices at 60 and 61 are each made up in amanner similar to the assembly shown in FIG. 5 except that the fluidinlet taps 62 and 63 respectively are laterally and downwardly directedwhile the fluid discharge taps 64 and 65 come out of the fittings 50 and51 respectively in an axial direction. In the view of FIG. 4 themodified flow distribution system is shown in connection with the upperback-up roll neck where the reaction transmitted into the back-up rollfrom the upper work roll is predominately vertically upwardly.Therefore, the fluid supply and exhaust manifold 50 and 57 are connectedto distribute the temperature control fluid over the area of maximumload reaction because it is in this area where the bearing loadsgenerate the greatest heat.

It should be understood in looking at FIG. 4 that the same fluid flowsystem when applied to the roll neck bearings for the lower back-up roll14 will be just the opposite to the fluid flow arrangement shown in FIG.4. That is to say, the manifolds 50 and 57 will be at the bottom and thefluid flow devices 60 and 61 will be at the top, with all of the partsin the same relative changed positions.

In high speed strip rolling means a major problem as has been pointedout, is the difficulty of controlling the strip flatness because of thecontinuous change in the variables which affect flatness. It is alreadynoted that flatness varies with such things as the character of thematerial being rolled, the strip thickness and width as well as theamount of reduction being produced, the variations in strip temperatureand hardness as well as the tension applied to the strip, and thetemperature rise which occurs in the rolls and in the roll bearings. Itis known that some of the variables mentioned change more or lessgradually throughout the run period of the rolling mill, some changesoccur gradually between the starting and finishing ends of the coilstrip, while still others may change abruptly from one coil strip toanother. It is the intention of the present disclosure to set forth atemperature and shape control system where the heat generated in theback-up rolls is balanced along its length by introducing or removingheat from the bearings and the bearing housing at the ends where theroll necks are mounted. The present system may be operated to take awayheat from the bearing areas or add heat to the roll ends so as toproduce th desired heat balance and temperature characteristics acrossthe width of the back-up rolls. It is preferred herein to implement thedisclosure in terms of the circulation of a heat control fluid such aswater and to provide control valves which are thermostatically modulatedin terms of the desired heat levels to be maintained at the criticalareas of the rolling mill. While the present system has been disclosedin connection with controlling the temperature characteristics acrossthe length of back-up rolls, it is understood that provisions similar tothose disclosed in FIGS. 2, 3 and 4 may be applied to the roll necks atthe opposite ends of the upper and lower work rolls, but such disclosurehas been understandably omitted so as to simplify the description anddrawings.

In the present disclosure a system has been described for controllingheat in the back-up rolls l3 and 14. The heat in these rolls (FIG. 2) isintroduced or removed by the bearings 22 at the necks 13a and 14a or atthe center of the rolls l3 and 14 by the product S being rolled.

The heat balance in each of the back-up roll necks 13a and 14a (FIGS. 1and 2) is subject to the control effected by temperature sensingthermocouple means 39. Each thermocouple means 39 is connected by a lead49 into an electrical buss in the protective tube 66. The lead 49 is, ineach instance, electrically united with lead 49' which connects to asuitable control mechanism generally shown at 46. The mechanism 46 isconnected to the adjacent valve 38 so that the temperature in the rollneck can be regulated by flow of the heat transfer fluid through conduit30. Thus, the thermocouple 39 by measuring the temperature of a suitableplace in the chock 17 and 18 modulates the mechanism 46 which opens orcloses valve 38 in response tothe desired heat transfer to maintainaccurate results in rolling the work strip S. The general mechanism of46 may be a Leeds and Northrup series 10260 drive mechanism for anelectric valve controller which, in turn, may be a Leeds and NorthrupElectromax III universal controller forapplications with thermocouples39, or an equivalent. The latter operates valve 38.

In FIG. 1 there is shown a system for controlling the heat balance inthe roll neck bearings as the load on the bearings contributes to thegeneration of heat. In this system, the heat transfer fluid suppliedfrom conduits 41, exits at conduits 45 to valves 36 and to the returnconduit 34. The valves 36 are each under the control of mechanism 48which is similar to mechanism 46 described above. As before, thethermocouples 39 are electrically connected into the buss in tube 66,and a lead 48' extends therefrom for connection at mechanism 48. It isunderstood that when the thermocuples vary from a predetermined settingheat balance is ei ther retained by the closing of one or more of thevalves 36 and 38, or by the opening of one or more of valves 36 and 38.Of course, the valves 36 and 38 can be modulated between open and closedpositions.

In FIG. 6 there is shown an arrangement of components which constitutethe mechanism of components 46 heretofore-described. For example, lead49 and 49' from a thermocouple 39 is connected to the valve controllerdevice VC that operates a prime mover PM connected by suitable links tothe valve 38. The valve 38 may control the flow of heat exchange fluidfrom line 30 to line 34 which leads back to the heat exchanger 37. Thedevices VC and PM may be Leeds and Northrup components heretoforeidentified in the description of FIGS. 1 and 2.

The present system, therefor, includes means whereby heat may be takenaway from or added to the roll ends or necks to produce or maintain adesired heat balance and temperature gradient across the width of theroll, and therebymaintain the desired roll shape which determines theflatness of the product S being rolled. While the disclosure has shownthe system applied only to the back-up rolls it is understood the samesystem is adapatable to the work rolls.

What is claimed is: 1. Apparatus to control the heat balance andtemperature gradient across the rolls of a mill for rolling stripmaterial to a uniform thickness, said apparatus includmg:

a. cooperating strip material work rolls and back-up rolls engaged withsaid work rolls, said rolls having necks for the operative supportthereof, b. vertical housings formed with windows, 0. chocks slidablymounted in said windows and bearings carried by said chocks 1. said rollnecks being supported in said bearings, d. a fluid circulating systemconnected into said chocks adjacent said roll neck bearings, said systemhaving 1. fluid heat exchanger means and circulating pump means inseries connection and 2. circulating flow control means connected intosaid system in advance of said heat exchanger, said control means beingresponsive to temperature adjacent said roll necks to selectivelyincrease and decrease the fluid circulation in said chocks and bearingsand balance the heat rise in said back-up rolls.

2. The apparatus of claim 1 wherein said circulating flow control meansincludes thermostatically controlled valve means adjacent each of saidroll neck bearings, said valve means individually regulating the rollneck bearing heat rise in accordance with predetermined heat balancerequirements of each'roll neck bearing.

3. The apparatus of claim 1 wherein said circulating flow control meansincludes temperature sensing means adjacent said roll neck bearings,valve means inserted in said fluid circulating system, and temperaturecontroller means connected between said temperature sensing means andsaid valve means whereby the heat 'rise in said bearings is balancedacross said work rolls.

5. The apparatus of claim 3, wherein said circulating flow control meansincludes thermostatically controlled valve means adjacent each of saidroll neck bearings.

6. In rolling mill apparatus including a framework and work and back-uprolls operably mounted by roll necks and supporting bearings in saidframework in a four-high roll assembly; the improvement of a roll shapeand temperature control system for said back-up rolls comprising, fluidflow passage forming means in said roll necks, separate fluid flowpassage forming means surrounding said bearings supporting said rollnecks, conduits connected to both said passage forming means to supplyfluid to and receive fluid from said passage forming means, heatexchange means connected to said fluid supply and receiving conduitmeans, pump means disposed in said system to cause fluid flow, heatresponsive means in the framework carrying said'bearings, and valvemeans in said fluid receiving conduit connections, said valve meansbeing connected to said heat responsive means and operated thereby tomodulate the fluid flow in both said fluid flow passage forming meansand cause said back-up -rolls to operate at a predetermined temperatureand shape in response to the temperature conditions in said roll necksand supporting bearings.

7. In rolling mill apparatus the improved combination of means tocontrol the temperature and shape of rolling mill rolls, comprising apair of work rolls to produce strip material of uniform thickness andwidth, a backup roll in rolling engagement with each work roll, eachback-up roll having roll necks, bearings supporting said roll necks, andmeans to control the heat generated in said roll necks to obtain heatbalance across the length of said back-up rolls, said control meansincluding fluid flow means connected into each roll neck to circulatefluid internally of each roll neck, fluid conducting jackets externallyadjacent said roll necks and bearings, conduits connected to saidinternal flow means and to said external jackets, heat transfer fluidcontained in said conduits, pump means operative to circulate said fluidthrough said conduits and jackets, heat exchanger means connected intosaid conduits and pump means, temperature measuring means adjacnet saidroll neck bearing supporting means responsive to temperature at saidbearing means, and valve means responsive to said temperature measuringmeans to modulate said fluid circulation selectively to add and withdrawheat at said roll necks.

t i I i

1. Apparatus to control the heat balance and temperature gradient acrossthe rolls of a mill for rolling strip material to a uniform thickness,said apparatus including: a. cooperating strip material work rolls andback-up rolls engaged with said work rolls, said rolls having necks forthe operative support thereof, b. vertical housings formed with windows,c. chocks slidably mounted in said windows and bearings carried by saidchocks
 1. said roll necks being supported in said bearings, d. a fluidcirculating system connected into said chocks adjacent said roll neckbearings, said system having
 1. fluid heat exchanger means andcirculating pump means in series connection and
 2. circulating flowcontrol means connected into said system in advance of said heatexchanger, said control means being responsive to temperature adjacentsaid roll necks to selectively increase and decrease the fluidcirculation in said chocks and bearings and balance the heat rise insaid back-up rolls.
 2. The apparatus of claim 1 wherein said circulatingflow control means includes thermostatically controlled valve meansadjacent each of said roll neck bearings, sAid valve means individuallyregulating the roll neck bearing heat rise in accordance withpredetermined heat balance requirements of each roll neck bearing. 2.circulating flow control means connected into said system in advance ofsaid heat exchanger, said control means being responsive to temperatureadjacent said roll necks to selectively increase and decrease the fluidcirculation in said chocks and bearings and balance the heat rise insaid back-up rolls.
 3. The apparatus of claim 1 wherein said circulatingflow control means includes temperature sensing means adjacent said rollneck bearings, valve means inserted in said fluid circulating system,and temperature controller means connected between said temperaturesensing means and said valve means whereby the heat rise in saidbearings is balanced across said work rolls.
 4. The apparatus of claim3, wherein said valve means includes prime mover drive means, and saidtemperature controller modulates said drive means.
 5. The apparatus ofclaim 3, wherein said circulating flow control means includesthermostatically controlled valve means adjacent each of said roll neckbearings.
 6. In rolling mill apparatus including a framework and workand back-up rolls operably mounted by roll necks and supporting bearingsin said framework in a four-high roll assembly; the improvement of aroll shape and temperature control system for said back-up rollscomprising, fluid flow passage forming means in said roll necks,separate fluid flow passage forming means surrounding said bearingssupporting said roll necks, conduits connected to both said passageforming means to supply fluid to and receive fluid from said passageforming means, heat exchange means connected to said fluid supply andreceiving conduit means, pump means disposed in said system to causefluid flow, heat responsive means in the framework carrying saidbearings, and valve means in said fluid receiving conduit connections,said valve means being connected to said heat responsive means andoperated thereby to modulate the fluid flow in both said fluid flowpassage forming means and cause said back-up rolls to operate at apredetermined temperature and shape in response to the temperatureconditions in said roll necks and supporting bearings.
 7. In rollingmill apparatus the improved combination of means to control thetemperature and shape of rolling mill rolls, comprising a pair of workrolls to produce strip material of uniform thickness and width, aback-up roll in rolling engagement with each work roll, each back-uproll having roll necks, bearings supporting said roll necks, and meansto control the heat generated in said roll necks to obtain heat balanceacross the length of said back-up rolls, said control means includingfluid flow means connected into each roll neck to circulate fluidinternally of each roll neck, fluid conducting jackets externallyadjacent said roll necks and bearings, conduits connected to saidinternal flow means and to said external jackets, heat transfer fluidcontained in said conduits, pump means operative to circulate said fluidthrough said conduits and jackets, heat exchanger means connected intosaid conduits and pump means, temperature measuring means adjacnet saidroll neck bearing supporting means responsive to temperature at saidbearing means, and valve means responsive to said temperature measuringmeans to modulate said fluid circulation selectively to add and withdrawheat at said roll necks.